It may not appear so to the casual observer, but the typical refrigeration system in a supermarket is a fragile and complicated network of machines that requires a great deal of attention to function properly.
Moreover, the refrigerants that drive a refrigeration system — unlike the fuel that propels a car — have a tendency to leak out and evaporate into the atmosphere. Hy-Vee, West Des Moines, Iowa, which operates more than 200 stores, has a leak rate “well under” the 23% annual average for the supermarket industry cited by the U.S. Environmental Protection Agency, yet “more than $1 million in refrigerant gas still leaks away per year,” said Jon Scanlan, service administrator for the chain.
These characteristics — complexity, fragility and leakage — were the focus of much of the conversation at the Food Marketing Institute's Energy & Technical Services Conference, held Sept. 7-10 in Orlando, Fla.
The leakage issue has long captured the attention of the EPA, which requires food retailers to fix any system that leaks more than 35% of its refrigerant on an annual basis; that percentage is expected to come down in the agency's new regulation later this year, said Dave Godwin, an environmental engineer with the EPA.
As a party to the Montreal Protocol, the United States, through the EPA, will ban the production and import of ozone-depleting R-22 refrigerant for new equipment beginning in 2010. Food retailers are preparing for this ban by stockpiling R-22 and replacing it with non-ozone-depleting refrigerants known as HFCs (which, unlike R-22, do not contain chlorine in their molecular structure).
But retailers are also focused on a more fundamental aspect of refrigeration — keeping food cold or frozen. For example, Jonathan Perry, director of energy and maintenance for Farm Fresh, Virginia Beach, Va., described at the conference how the chain, a division of Supervalu, ensures the quality of refrigerated food by using a round-the-clock centralized alarm monitoring system to make sure that, among other things, freezer doors are not left open.
The impact of the monitoring system on preventing product loss at Farm Fresh has been impressive. A store that uses monitoring will experience at least $1,900 less in refrigeration losses annually than a store that does not use monitoring, said Perry. “Our numbers shot up on how much food we were selling when we really got a handle on this. For product loss alone, I would implement central monitoring.”
In fact, “during the past three years, for all intents and purposes, we have gotten rid of the vast majority of our refrigerated product loss,” Perry said. Stores with full monitoring “should not lose product,” he added.
There are other benefits as well. Perry conservatively estimated that the chain saves 2% on energy costs as a result of its monitoring system. The system prevents inefficiencies by giving Farm Fresh more control over setpoints for temperature and pressure readings and over devices like variable-frequency drives.
The system cuts down on maintenance calls and offers faster response times when maintenance is required. It also allows Farm Fresh to be “more predictive than reactive in our maintenance,” Perry said. It has even enabled the chain to stop a night crew from stealing thousands of dollars worth of steaks and seafood at one store.
Farm Fresh currently monitors 160 stores within the Supervalu umbrella, including all of its own 46 stores. The monitoring system's controllers are mainly from Emerson Climate Technologies Retail Solutions, Kennesaw, Ga., and use high-speed Ethernet lines in 70% of the system's connections.
To determine whether a walk-in freezer door has been left open, the system monitors door switches; for freezer cases on the sales floor, it checks temperature sensors. It also tracks a host of other factors, including the suction and discharge pressure of compressors, refrigerant levels and refrigerant leak detectors.
Unlike many retailers, Farm Fresh decided to operate its own monitoring system rather than outsource the task. “We felt we knew our stores better than an outside company,” said Perry. “And we felt the intelligence of the store was not something you subcontract out.” In addition to himself and a manager of central monitoring, Farm Fresh uses six central monitoring analysts/dispatchers and three backups in the 24-hour operation.
The cost of installing automated sensor technology like Farm Fresh's ranges from $40,000 to $60,000 per store, said Perry. In addition, a retailer would pay an outside monitoring company between $75 and $250 per month per store, or perform the monitoring function internally as Farm Fresh does, he added.
Farm Fresh's monitoring staff handles 600 to 1,500 alarms that need to be addressed each week. (Many more “nuisance alarms” caused by maintenance work and other factors are also received.)
Farm Fresh's first attempt at store monitoring took place in 2000, but that effort was far more limited, with temperature sensors on about 30% of the cases; it did not prevent considerable product loss.
Perry was eventually asked to take over responsibility for monitoring from maintenance (before the two functions were merged). He noticed that the monitoring system was allowing refrigeration in walk-in freezers to be left off for long periods of time — in a dozen cases, longer than six hours — without intervention by employees.
Perry began to personally respond to operational alarms — even in the middle of the night — contacting the vice president of operations, who dealt with store employees. The VP of operations “took calls from me for 14 months, sometimes five to six times a night,” said Perry, who soon became known as “Mr. Freezer Door Closer.” Separately, he performed manual checks of refrigerated cases and measured the labor costs to get a better sense of what the payback of a more fully automated system would be.
Farm Fresh finally concluded that the existing monitoring system and manual inspections were not sufficient. The chain began making adjustments in 2000 and 2001 and decided to make a much larger investment in the technology in 2002, with implementation taking place continuously since then. By 2005, the chain had upgraded the bulk of its stores and began monitoring other Supervalu stores.
LEAK PREVENTION
Hy-Vee took a different approach to managing its refrigerants and leak data than Farm Fresh. Rather than deploy an internal system, the chain went with a Web-based refrigerant management system hosted by Verisae, Minneapolis, said Hy-Vee's Scanlan, who spoke at the conference.
Before adopting the Verisae system in 2005, Hy-Vee had used a paper-based process to track its refrigerants and leaks. That did not provide “useful data,” said Scanlan. “We couldn't aggregate it.” By contrast, the Web-based system, into which technicians enter information on the amount of refrigerant added to a store's refrigeration system, allows the chain to know the exact cost of leaks.
The system is also “a great way to identify the source of leaks and work with contractors to correct them,” said Scanlan. “We have more than 95% confidence in it.” In addition, the system allows Hy-Vee to track the quality of refrigeration installations. “Installs are the key” to preventing leaks, he said. As a result, leak rates have dropped in each of the three years the system has been used, giving Hy-Vee a full return on its investment.
Hy-Vee also uses the system to comply with EPA record-keeping requirements and to gather data for carbon footprint, climate registry and other initiatives.
Some hurdles Hy-Vee faced in implementing the system included accumulating accurate data on equipment for its stores, which took about a year, as well as educating its contractors and ensuring that they used the system.
Wal-Mart Stores, Bentonville, Ark., is among those retailers that have made significant strides in replacing their R-22 refrigerant with alternative HFC refrigerants that don't harm the ozone layer (though they still contribute to global warming). According to Richard Royal, mechanical design manager, prototypical design for Wal-Mart, who spoke at the conference, Wal-Mart has retrofitted 561 stores with an HFC refrigerant — 302 with R-404A, 253 with R-422D, four with R-422A, one with R-407A and one with R-427A.
Wal-Mart no longer uses R-404A because of its cost and its global warming potential. “R-422D and the R-407 series are acceptable,” said Royal. “They perform without a lot of complications.”
New refrigerants can have a variety of impacts on a refrigeration system. For Wal-Mart, the effect on the sizing of refrigerant pipes “is the biggest show-stopper,” Royal said. “We can't afford to re-pipe a significant amount of our stores.”
There is also a potential for new leaks after a conversion, he added. Wal-Mart had an increase in leak rates when it began doing retrofits “until we learned how to do it,” he said. “We had significant adjustments to make.”
BETTER STARTS
In another conference session, Ed Estberg, senior director, facilities, for Raley's, West Sacramento, Calif., described his efforts to improve the start-up and management of the motors on his stores' refrigerator compressors, the linchpin of any refrigeration system.
Raley's tried a variety of soft-starter devices — which reduce the stress during start-up — on its compressor motors over the past eight years before finally finding an acceptable one from Motortronics, Clearwater, Fla. Although he no longer has maintenance problems with the motors, Estberg was persuaded to test the use of an Allen-Bradley variable-speed drive from Rockwell Automation, Milwaukee, on the motors instead of a soft-starter.
“We could immediately tell the difference,” he said. “The motors started better and sounded better.” The speed of the motors could be reduced to 600 rpm. The drives also reduced cycling, extending the life of components, and stabilized the suction pressure of the compressors.
It appeared that Raley's would be able to save enough energy with the variable-speed drive to justify a chainwide rollout. However, after running a year-long test on six compressors in a new store, Estberg determined the drives saved only 2% on the energy costs of refrigeration, and 0.8% for the store overall. That was not enough to replace the soft-starters chainwide. “Anything less than 5% could be from some other variation in the store,” he said.
However, with the other advantages of the drives, Raley's does plan to install them on compressors in new installations instead of soft-starters, though it will pay a $5,000 to $6,000 premium per store.